North Sea platform incident: Serious breaches come to light following worker injuries and gas leak

Norwegian state energy company Equinor has been issued a clean-up order by the country’s maritime safety regulator following an investigation into an incident that caused injuries and led to a gas leak at a North Sea platform located on one of the oldest producing fields on the Norwegian Continental Shelf (NCS). ).

Statfjord B; Source: Harald Pettersen/Equinor

Last year, an investigation was initiated into the incident on ul Statfjord B platform, which occurred on April 22, 2023, when the hub clamps/cap were removed from new production pipes. In addition to investigating the incident, the Norwegian Ocean Industries Authority (Havtil) provided technical support for the police investigation into what happened.

The incident occurred during the splitting of a blind hub on a new production pipeline, when it turned out that the installation was not completely depressurized. As a result, the pressure in the pipeline launched the 34-kilogram hub to a height of approximately 1.5 meters, which then hit the person coming down, breaking his nose and jaw. In addition, a 2.15 kg sealing ring fell to a lower level and struck a person there, without causing any injuries.

At the time of the incident, seven people were in the immediate vicinity while the blind hub of the hydrocarbon system was being broken down, and one person was also on the lower level. Stressing that the subsequent gas leak was short-lived and weighed approximately 2.4 kg, Havtil also stressed that under slightly different circumstances the incident could have turned into a fatal accident.

The Statfjord B platform stands on a platform operated by Equinor Statfjord Field located in the Tampen area in the northern North Sea, on the border of the Norwegian and British sectors. Equinor describes Statfjord as one of the oldest producing fields in the NCS and the largest oil discovery in the North Sea. The Norwegian share in the deposit is 85.47%, and the water depth in this place is 150 meters.

The Statfjord field, discovered in 1974, was developed using three fully integrated production platforms: Statfjord AStatfjord B i Statfjord C. Statfjord B in the southern part of the deposit was put into operation in 1982, and the Norwegian part of the deposit is located in blocks 33/9 and 33/12 in mining license 037, while the British part is located in British block 211/25 in licenses 104 and 293 .

The probe highlights lessons learned from the incident

Listing lessons learned from the incident, an investigation by the Norwegian Ocean Industries Authority found that an application for a work permit for the subdivision of a hydrogen installation was submitted, processed, approved and activated with an attached isolation plan that was unrelated to the job. to do.

Havtil emphasizes that this plan was not considered in connection with the safety clearance of the works, which could have happened because the plan was in a file attached to the work permit and which remained unopened throughout the permit processing period. It had a file name that could suggest it was related to a quest.

With this in mind, the maritime safety authority explains that the incident could have been avoided if the isolation plan attached to the work permit had been checked before it was put into operation, showing how important it is to follow established procedures.

Additionally, the Norwegian regulator found that operators failed to notice that the valve they chose to open contained a non-return valve when checking for depressurization in the system before splitting, which meant they incorrectly concluded that the system was depressurized. The design of the valve used for verification differs from other valves used to inject chemicals at the facility, but this was not known to the relevant personnel.

Additionally, Havtil is adamant that training and documentation are important factors in ensuring adequate knowledge of equipment when a facility has been in operation for a long time and has been modified by installing new-design equipment.

Nonconformities and points of improvement

Furthermore, the regulator’s investigation found four regulatory non-compliances in connection with the incident, including inadequate safety clearance of operations, inappropriate communication of information during shifts and crew changes, lack of information to appropriate users and failure to plan work. identify significant factors contributing to the risk of an ignition source.

In addition, the investigation team identified one condition that could be considered a point of improvement related to the inability to perform planned activities. Due to serious violations of regulations discovered during the investigation, Equinor received notice of the issuance of an injunction.

Accordingly, Havtil ordered Equinor to identify measures and establish a plan to implement measures to ensure compliance with operations security clearance requirements and the necessary communication of information on the status of isolation plans during shifts and crew changes. The Norwegian giant was also ordered to conduct an internal review to check whether the actions taken had the desired effect.

According to the Norwegian safety regulator, any comments on the notification could be submitted no later than April 22, 2024. The deadline for compliance with paragraph. 1 and 2 of the order expire on June 1, 2024, and on June 1, 2025 in point 3. Havtil must be notified if individual points of the order are met.